Solid state fuze select circuit

ABSTRACT

A circuit arrangement using inexpensive electrical fuzes in a solid state circuit for selecting different combinations of detonators by blowing different combinations of two fuzes depending upon the voltage and polarity of a signal applied thereto.

United States Patent McKenzie et al.

1451 May 22,1973

154] SOLID STATE FUZE SELECT CIRCUIT 3,306,208 2/1967 Bergey et a1 102/702 t 3,312,869 4/1967 Werner 102/70.2 X [75] Inventors: Joe A. McKenzie, Rlverslde; Iharles 3,453,496 7/1969 Wright et alm mum/702 x Engel, P 0f C8111 3,417,259 12/1968 Nozawa et al. ..1o2/7o.2 x

[73] Assignee: The United States of America as represented by the Secretary of the Primary ExammerSamuelFe1nberg Navy Washington DC Assistant Examiner-Thomas H. Webb Att0rney-R. S. Sciascia and J. M. St. Amand [22] F1led: Sept. 16, 1969 [21 Appl. No.: 862,629 ABSTRACT A circuit arrangement using inexpensive electrical [521 US. Cl. ..102/70.2 R fuzes in a solid state circuit r s l cting different [51] Int. Cl ,.F42c 11/00, F42 15/40, F42 19/12 combinations of detonators by blowing different com- 58] Field of Search ..102/70.2 binations of two fuzes depending upon the voltage and polarity of a signal applied thereto.

5 6] References Cited 3 Cl 1 Drawing Figure UNITED STATES PATENTS 3,045,148 7/1962 McNulty et a]. 102/702 UX DETONATOR o SIGNAL I VOLTAGE INPUT {57V 16 25 37 FIRING TRIGGER 2 [LF 26 T 39 DETONATOR 1 CRUSH TRIGGER PATENTE m2 21975 DETONATOR --o SIGNAL VOLTAGE INPUT 3 Kn J 7 I6 25 f FIRING O- E 2| l6 Kn TRIGG R 2p 26 T r DETONATOR I Mn.

CRUSH TRIGGER JOE A. M KENZIE CHARLES E. ENGEL INVENTORS ATTUHNI; f

SOLID STATE FUZE SELECT CIRCUIT The invention herein described may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefore.

The present invention relates to firing circuits for electronic fuze systems and in particular to circuitry using solid state devices to provide a safe and reliable system for selecting combinations of detonators.

Prior systems used gaseous discharge devices to detect potentials applied to either blow the desired fuzes or leave them in their normal state. These devices had wide variations in their performance characteristics which made them unreliable under certain temperature conditions. Further, radioactive discharge tubes posed a handling problem since they were quite hazardous if accidentally broken thereby releasing the radioactive material into the immediate area. Also, some prior systems used expensive explosive switches.

The invention described herein operates over a wider range of input voltages permitting greater energy to be delivered to fuzes for greater reliability and selectivity than in prior systems. No changes in circuit performance result from aging, extensive testing, or temperature extremes as in prior devices, and no hazards are involved in the components used. Inexpensive electrical fuzes are used rather than expensive explosive switches.

Other objects and many of the attendant advantages of this invention will become readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

The FIGURE shows a schematic of the circuit of a typical embodiment of the present invention.

Using the values as shown in the FIGURE of drawing for the various components of the circuit, the voltage applied and its polarity result in various fuze conditions as shown in the table below:

Voltage Applied Fuze Condition a. +300V 31 and 32 normal b. +195V 31 blown; 32 nonnal c. l95V 31 and 32 blown d. 300V 31 and 32 blown The circuit shown includes a triac which is a bidirectional device in combination with bidirectional breakdown diodes 12 and 13 and with unidirectional diodes 11 and 14. The signal voltage is applied to input 16. During the select process terminal 17 is grounded, and terminals 18, 19 and 20 are open.

For condition a. shown in the Table, the time constant of the circuit formed by resistors 21, 22 and capacitor 23 is much smaller than the time constant of the circuit formed by resistor and capacitor 26. The signal voltage input to terminal 16 determines in what combination fuzes 31 and 32 will be blown as shown in the above table, for example.

When +300 volts is applied to input terminal 16, capacitor 23 charges through the divider of resistors 21 and 22 to a potential which exceeds the threshold voltage of bidirectional breakdown diode l3. Diode 13 exhibits a negative resistance region thereby delivering a part of the charge in capacitor 23 to resistor 27 and the gate of triac 10 through resistor 28 which limits the cur- 6 pacitor 26 acquires sufficient charge to blow fuze 31. Due to the aforementioned time constants, the energy stored in capacitor 26, during the time of the above action, is far below the energy required to blow fuze 31. Once triac 10 is on it remains on drawing the current through resistor 25 and fuze 31 for the duration of this condition. This direct current is not sufficient to blow fuze 31, therefore fuze 31 is left in its normal condition, and fuze 32 is protected by diode 14. Resistor 33 forms a leakage path which maintains a discharge condition on capacitor 26 when the circuit is not in operation.

For condition b. in the Table, when a signal voltage of +195 volts is applied to input terminal 16, the divider formed by resistors 21 and 22 provides a potential to capacitor 23 which is less than the threshold of diode 13 and thus capacitor 23 makes no contribution to the operation. Consequently, capacitor 26 charges toward the +195 volts, and when the potential exceeds the threshold of diodes 12 and 13 (about 160 volts), both diodes exhibit the negative resistance characteristics and a small amount of charge from capacitor 26 is delivered to resistor 27 and the gate of triac 10 through diodes 12 and 13, and resistors 28 and 29 thereby turning on triac 10. Triac 10 then delivers the energy stored in capacitor 26 to fuze 31, causing the fuze to blow. Fuze 32 remains normal because of diode 14.

During conditions c. and d. in the Table, when a negative potential is applied to input 16, diode 11 prevents resistors 21 and 22 and capacitor 23 from having any effect on the circuit operation. Since diodes 12, 13 and triac 10 are bidirectional elements, the circuit action is the same as for condition b. except that diode 14 now conducts allowing fuze 32 to also receive energy from capacitor 26. Therefore, both fuzes 31 and 32 are blown after either --1 volts or 300 volts have been applied to signal voltage input 16. Thus greater reliability of selectivity is obtained with a greater range of input signal.

Following the select process, an arming processes causes: the switch at terminal 17 to be opened leaving only crush trigger 36 connected at that point; the switch at terminal 18 is closed connecting in a firing trigger 37; the switches at terminals 19 and 20 are closed connecting detonators 38 and 39, respectively, having different delay times.

After arming: under condition a., where both fuzes 31 and 32 are normal, both detonators 38 and 39 can be fired from a signal from either firing trigger 37 or crush trigger 36; under condition b., where fuze 31 is blown and fuze 32 is normal, a signal from firing trigger 37 cannot detonate either detonators, but crush trigger 36 can provide a signal to both detonators; under conditions 0. and d., where both fuzes 31 and 32 are blown, firing trigger 37 cannot cause either detonator to fire, but crush trigger 36 can cause detonator 38 to fire.

What is claimed is:

1. A circuit for selecting combinations of detonators, comprising:

a. a signal input terminal and a ground terminal,

b. first and second resistors connected in series between said signal input and ground terminals respectively, forming a first voltage divider,

c. a first capacitor means connected across said second resistor,

d. third and fourth resistors connected in series between said signal input and ground terminals respectively, forming a second voltage divider,

e. a second capacitor having one end connected to the junction of said third and fourth resistors and the other end operable to be connected to said ground terminal,

f. first and second bidirectional breakdown diodes,

g. first and second current limiting resistors having one end connected respectively to one side of said first and second bidirectional breakdown diodes,

h. a first unidirectional diode having its anode connected to the junction of said first and second voltage divider resistors and its cathode connected to the other side of said first and second bidirectional breakdown diodes,

i. a triac having a gate and first and second main terminals, the first main terminal of said triac being connected to said ground terminal,

j. the other end of said first current limiting resistor being connected to the second main terminal of said triac, and the other end of said second current limiting resistor being connected to the gate of said triac,

k. a current bypass resistor connected between the gate of said triac and said ground terminal,

I. a first electrical fuze connected between the junction of said third and fourth resistors and the second main terminal of said triac,

m. a second electrical fuze also having one end connected to the junction of said third and fourth resistors,

n. a second unidirectional diode having its anode connected to the second main terminal of said triac and its cathode connected to the other end of said second electrical fuze,

o. a first detonator means operable to be connected between the second main terminal of said triac and said ground terminal,

p. a second detonator means operable to be connected between the junction between said third and fourth resistors and said ground terminal,

q. a first trigger means operable to be connected between the second main terminal of said triac and said ground terminal,

. a second trigger means connected between said second capacitor means and said ground terminal,

5. said circuit being set for select process when said second capacitor means is connected to ground terminal and first and second detonator means and said first trigger means are not connected in circuit, whereby various fuze conditions can be selected depending upon the voltage applied to said signal input terminal and its polarity,

. said circuit being set in armed condition where said second capacitor means is disconnected from said ground terminal and said first and second said detonator means and said first trigger means are connected in circuit whereby desired ones of said detonators are detonated by any of said first and second trigger means.

2. A circuit as in claim 1 wherein said first trigger means is a proximity device.

3. A circuit as in claim 2 wherein said second trigger means is a crush trigger. 

1. A circuit for selecting combinations of detonators, comprising: a. a signal input terminal and a ground terminal, b. first and second resistors connected in series between said signal input and ground terminals respectively, forming a first voltage divider, c. a first capacitor means connected across said second resistor, d. third and fourth resistors connected in series between said signal input and ground terminals respectively, forming a seconD voltage divider, e. a second capacitor having one end connected to the junction of said third and fourth resistors and the other end operable to be connected to said ground terminal, f. first and second bidirectional breakdown diodes, g. first and second current limiting resistors having one end connected respectively to one side of said first and second bidirectional breakdown diodes, h. a first unidirectional diode having its anode connected to the junction of said first and second voltage divider resistors and its cathode connected to the other side of said first and second bidirectional breakdown diodes, i. a triac having a gate and first and second main terminals, the first main terminal of said triac being connected to said ground terminal, j. the other end of said first current limiting resistor being connected to the second main terminal of said triac, and the other end of said second current limiting resistor being connected to the gate of said triac, k. a current bypass resistor connected between the gate of said triac and said ground terminal, l. a first electrical fuze connected between the junction of said third and fourth resistors and the second main terminal of said triac, m. a second electrical fuze also having one end connected to the junction of said third and fourth resistors, n. a second unidirectional diode having its anode connected to the second main terminal of said triac and its cathode connected to the other end of said second electrical fuze, o. a first detonator means operable to be connected between the second main terminal of said triac and said ground terminal, p. a second detonator means operable to be connected between the junction between said third and fourth resistors and said ground terminal, q. a first trigger means operable to be connected between the second main terminal of said triac and said ground terminal, r. a second trigger means connected between said second capacitor means and said ground terminal, s. said circuit being set for select process when said second capacitor means is connected to ground terminal and first and second detonator means and said first trigger means are not connected in circuit, whereby various fuze conditions can be selected depending upon the voltage applied to said signal input terminal and its polarity, t. said circuit being set in armed condition where said second capacitor means is disconnected from said ground terminal and said first and second said detonator means and said first trigger means are connected in circuit whereby desired ones of said detonators are detonated by any of said first and second trigger means.
 2. A circuit as in claim 1 wherein said first trigger means is a proximity device.
 3. A circuit as in claim 2 wherein said second trigger means is a crush trigger. 